AS if the murky drugs underworld wasn't already dangerous enough, health experts are concerned a wave of new designer narcotics are set to sweep into Gloucester.
A recent trend of heroin being cut with lethal anthrax and tetanus by dealers looks to be coming to an end, but the latest cheap black market substitutes are proving just as deadly.
Dr Allan Harris has spent the last 15 years running a weekly clinic at the Vaughan Centre in Southgate Street.
He specialises in treating the homeless, drug and alcohol addicts or people without access to a regular GP. He has noticed a worrying new trend beginning to develop.
"Signs that anthrax was getting into the heroin supply first appeared in Gloucester two years ago," he said.
"Dealers are not too bothered what they cut it with, usually something with a bitter taste, like strychnine. MCat is also used. It is pretty horrible stuff and makes the skin smell of fish. It sends people psychotic."
Now, he is warning of a new wave of "cheap and nasty" drugs on the brink of joining mephedrone, or MCat, as the major problem on the city's streets.
"Crystal Meth is a lot stronger but has a similar pattern. It is scary stuff," he said. "We haven't seen much of it in Gloucester, but that could change. It is getting closer to Gloucester.
"Another drug coming into fashion is Krokodil. It causes nasty necrosis, or cell death.
"It has come from Russia and is very unpleasant. There are plenty of warning signs that it could be in Gloucester.
"It is cheap and nasty and causes damage to the point where you can see someone's bones through their skin.
"There is a raft of similar drugs and it is a nightmare for legislation.
"As soon as one drug is banned or categorised, another one becomes available.
"They are all too readily available."
He added: "These new drugs are putting emergency services under more pressure, all these things have a huge implications for workload. Most of the mental issues we treat are associated to drugs."
In the past four years the serious and organised crime unit at Gloucestershire Police has helped convict more than 100 people in the county for class A drugs and other serious offences.
Detective Inspector Ian Fletcher said officers are yet to encounter cases of crystal meth and Krokodil, but have real concerns over the spread of mephedrone.
"Both cocaine and mephedrone remain serious concerns for us in the Gloucester area and we are tackling the supply of these drugs on several fronts," he said.
"The crime operations team are carrying out warrants every week, often based on community information to tackle the supply of drugs."